By Jeff Mason

NANTUCKET, Mass. President Joe Biden praised U.S. diplomacy behind Friday's release of 24 hostages held by Hamas fighters, saying it was the start of what he expected would be further hostage releases by the Palestinian militant group in the coming days.

"Beginning this morning, under a deal reached by extensive U.S. diplomacy, including numerous calls I've made from the Oval Office to leaders across the region, fighting in Gaza will halt for four days," Biden told a news conference.

Biden declined to speculate about how long the Israel-Hamas war would last, but said he thought the chances of an extension of the ongoing truce were "real." He also expressed hope that American nationals held by Hamas would be freed.

"I don't know how long it will take," Biden said.

"My expectation and hope is that as we move forward, the rest of the Arab world and the region is also putting pressure on all sides to slow this down, to bring this to an end as quickly as we can."

Hamas fighters released 24 hostages on Friday during the first day of the war's truce -- including 13 Israeli women and children, 10 Thai farm workers and a Filipino -- after guns fell silent across the Gaza Strip for the first time in seven weeks.

The hostages were transferred out of Gaza and handed over to Egyptian authorities at the Rafah border crossing, accompanied by eight staff members of the International Committee of the Red Cross (ICRC) in a four-car convoy, the ICRC said.

(Reporting by Jeff Mason; Additional reporting by Kanishka Singh, Phil Stewart and Idrees Ali; Writing by Kanishka Singh and Phil Stewart; Editing by Daniel Wallis and Leslie Adler)